1. Field of the Invention
The present invention relates to the field of building construction and more particularly to the joints between vertical columns and horizontal beams, and is particularly useful in lift-slab type construction for multi-story structures.
2. Description of the Prior Art
The joints between vertical columns and horizontal beams are of two categories, depending upon the desired transmission of loads from the beam to the column. Conventional construction methods have utilized structural steel frameworks for individual floors, by assembling the steel members at succeeding story heights above ground level. The complexity of total assembly of the components at each succeeding higher elevation is apparent. Generally speaking, this type of construction has utilized beams which are discontinuous at the columns, the beams being merely bolted to the column flanges to act as a shear type connection. If the design of the structure required a moment type connection utilizing a continuously acting beam, rather than a shear type connection, the beam ends were welded to the column and flanges and fillers were provided to extend between the column flanges such that after the fillers were welded in place, the joint would cause rotation of the column in response to rotation of the beam. Thus, the constructional requirements for a moment type connection were vastly different than the structural requirements for a shear type connection. The prior art contains many teachings for the construction of shear joints and moment joints, but simplicity and versatility have not been key factors. Quite importantly, the prior art teachings are not generally usable in the case of modern lift-slab construction techniques.